1. Field of the Invention
The present invention relates to a bone graft substitute and a method of manufacturing the same, and more particularly, to a bone graft substitute using calcium phosphate compounds and a method of manufacturing the same, in which the bone graft substitute is used for recovering bone defects damaged due to a bone fracture using calcium phosphate compounds.
2. Description of the Related Art
In general, a classical and general bone graft is an autograft. The autograft has advantages of good osteogenic capacity and having no risks of infection of infective diseases or immune response. However, it is difficult to obtain a sufficient amount of bones from patient, and inflammation may occur in a donor site. Thus, an allograft or xenograft is not satisfactory due to difficulties of obtaining bones to be grafted through a bone bank, or problems of a delay in a bony union together with risks of infection of infective diseases and immune response.
In order to solve the above-described problems, a recent research and development of bone graft substitute of osteogenic capacity similar to autograft has been being extensively performed.
Calcium phosphate compounds get into the spotlight as candidates for bone replacement. Hydroxyapatite (HA, Ca10(PO4)6(OH)2) is a principal inorganic component occupying a bone mass of 60–70%. The HA is superior in view of biocompatibility and has good osteoconductive property. Thus, studies of developing the HA ceramics into bone graft substitutes and applying the same clinically have been being vividly proceeded.
However, since the HA ceramics have a very low solubility in a living body, it remains in the body for a long time. As a result, a complete replacement of new bone is hindered.
There are a number of calcium phosphate compounds which can be used as a bone graft substitute. A representative one among them is tricalcium phosphate (TCP; Ca3(PO4)2), or calcium pyrophosphate (CPP; Ca2P2O7) in addition to the HA.
A variety of calcium phosphate compounds vary in dissolution rate in a living body, respectively. It is known that the extent of dissolution decreases in the following order: CPP>TCP>>HA. A material of rapid dissolution in the body is called a biodegradable material, which includes TCP and CPP.
An ideal biodegradable material should keep strength and durability during slow degradation to accomplish a complete substitution into a new bone. Also, it has an dissolution rate which is possibly identical to a bone growth rate. However, any materials which meet all the above-described conditions has not been found yet.
By the way, optimal compounds or compositions which may be consistent with the above-described conditions can be determined by adjusting a composition of calcium phosphate compounds whose solubilities in a living body differ from each other appropriately.